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Paeonia rockii has been a traditional medicinal material from time immemorial. It is an important plant resource of ethnic medicine and chinese herbal medicine. It has unique effects on heat and cool blood, promoting blood circulation and dispersing blood stasis, analgesia and promoting menstruational flow. It is also a first-class protected plant. With the increasing demand for the bark and roots of P. rockii in China's medicinal market, the continuous high-intensity and disorderly excavation has led to a sharp decline in wild resources. P. rockii is in imminent danger and needs to be saved and protected urgently. In this study, the distribution records of P. rockii in China, combined with environmental factors, are used to simulate the current potential distribution area of P. rockii through MaxEnt model. The environmental factors affecting the distribution of P. rockii are obtained by using the contribution rate of environmental factors and a jackknife test analysis, and the appropriate value of environmental factors is determined by using the response curve. The results show that the AUC value of test set data is 0.985 and that of training set data is 0.987. The prediction accuracy of the Maxent model is extremely high and the simulation effect is very good. At present, the high suitable areas of P. rockii are mainly distributed in the shape of cake in Southern Ningxia, southern Gansu and southern Shanxi, accounting for 15.58% of the total suitable areas. The most important environmental factor affecting the geographical distribution of P. rockii is the altitude; Under the future climate change scenario, the total suitable area of P. rockii shows a decreasing trend, among which the area of high suitable area shows an obvious decreasing trend, the mass center of high suitable area of P. rockii generally tends to migrate to the northwest, and the migration range is large under the scenario of high concentration emission. The research results can provide scientific data support for P. rockii to to cope with the changes in suitable areas caused by climate change and the establishment of effective protection, clarify the change and heterogeneity of P. rockii in different regions of China in the future, and clarify its ecological needs, which has certain practical significance. [ABSTRACT FROM AUTHOR]

Alien invasive algae along with ship ballast water have posed a serious threat to China's marine ecological security. A clear understanding of the geographical distribution of invasive species and their response to climate change can provide a scientific basis for their prevention and control. In this study, combined with environmental variables and distribution data, MaxEnt was used to predict the potential geographical distribution and change trend of Alexandrium in the four major sea areas of China currently, 2040s (2040-2050) and 2090s (2090-2100), reveal the dominant environmental factors affecting the geographical distribution, analyze the migration trends of centroids the highly suitable area, and clarify the key control sea areas. The results showed that: 1) The AUC values of all models were significantly higher than random models, and the Kappa statistics of all models were higher than "general", demonstrated that the prediction results were available. 2) The most important environmental variable affecting the geographical distribution of Alexandrium was the Temperature. Range (bio24), and its suitable range was 23.43-31.52°C. 2) At present, in the corresponding sea areas of Nantong, Yancheng, Ningbo, Jiaxing, Dongying, Binzhou, Cangzhou, Tianjin, Tangshan, Qinhuangdao, Shenzhen, Dongguan and Zhongshan, special attention should be paid to the control of Alexandrium. 3) Under the future climate change scenarios, excepted in the South China Sea, the total and highly suitable area of Alexandrium showed an increasing trend. 4) Under climate change scenarios, in the Yellow Sea, the centroids of the highly suitable area would move to the southeast. In the Bohai Sea and the East China Sea, the centroid showed a trend of moving to different latitudes and directions. In the South China Sea, the centroids of of the highly suitable area and total suitable area of Alexandrium would both move to the southwest. Our results can provide a theoretical basis for the prevention and control of Alexandrium. [ABSTRACT FROM AUTHOR]